Electrode.



J. Mania. ELECTRODE. APPLICATION FILED APR. 27,1905.

1 $245,257, Patented Apr. 23, 1912.

Witnesses: H Inventor:

Johannes Hrde'n may be employed in electrodes TRIC COMPANY, A CORPORATION OF NEW YORK.

ELECTRODE.

T 0 0.7L whom it may concern:

Be it known that I, JOHANNES Hiinnx,

a subject of the King of Norway and Sweden,

position of are light electrodes and more particularly to thecomposition of electrodes of the character which yield so called flamingor luminous arcs.

My present invention consists of an electrode, one of the principalconstituents of which is the substance boron. The boron varying incomposition and the manner of their production. I have obtainedexcellent results in the following manner: A mixture conta-in'iiigapproximately two parts of boron anhydrid in the form of a coarse powderandone part of alumimm in the form of .small lumps or pieces is firstheated slowly in a suitable crucible such as a Hessian crucible in whichthe expansion of the mass can take place without danger to the crucible.After the initial heating at comparatively low temperature the mixtureis placcd in a refractory crucible not attacked by boron, such as acrucible formed of magnesia which may in turn be placed in a graphitecrucible'and is heated for a short time at a high temperature, say thatof 2300 degrees ccntigradc. After this heatimg the mass allowed to coolslowly. The heating of the mass and its subsequent cooling in the'n'ianner described results in the crystallization into needle crystalsof the boron in whatever form it may be. I have found that the form ofcrystallization is important as much less satisfactotry results areobtained when the boron is not crystallized as described.

After the crystallized material is cooled it is treated with acid todissolve the free aluminum, and then treated with alkali to remove theacid residue, after which it is washed in water. The aluminum oxid 1Sseparated out in any suitable manner.

The crystallized boron is then powdered and mixed "with carbon, andheated in a carbon crucible in an electric furnace. This converts theboron into a compound which I believe to be boron carbid, probably hav-Speciflcation of Letters Patent. T Application filed April 27, 1905.

Patented Apr. 23, 191%.. Serial no. 257,580.

ing the composition B C. The material thus formed is mixed -with carbonand titanium carbid to form a mixture from which electrodes are made.tions of carbon, titanium'carbid, and boron compound employed may ,yarysomewhat. In one form of my invention I use a mixture containingsubstantially Lparts or" titanium carbid, 20 parts of the boroncompound, and 20 parts of carbon. In a second form I employsubstantially 40 parts of.

titanium carbid, 40 parts of the boron compound and 20 parts of carbon.In a third form I employ substantially 20 parts of lllillllll m carbid,60 parts of the boron compound, and 20 parts of carbon. The first formof electrode is consumed with. comparative slowness by the arc and givesan efficient amount of light off a good color. The second form givesslightly less light than the first, but the are obtained is more steady.The third form gives a steady fat are. This form of electrode isconsumed more rapidly however than either of-the first two, and thelight obtained has a. greenish tinge.

In forming electrodes from mixtures described above, the mixture isfirst powdered and then moistened and mixed with a suitable binder suchas tar. Electrodes are then molded or squirted from the mixture in theusual manner. The formed electrodes are first slowly dried to remove thewater contained by them and are then hardened by baking ina suitablefurnace such as a carbon tube electric furnace, After the electrode ishardened by baking it is copper-plated to prevent oxidation under theconditions of service. The conductivity is good.

Any of the electrodes described above possess excellent light-givingproperties and can be advantageously used both in alternate and directcurrentlamps. When used in direct current lamps, the electrodecontaining boron may advantageously be employed as a negative electrodein conjunction with a positive nonconsuming electrode. in an alternatecurrent lamp two similar electrodes of the character described above maybe employed as the arching terminalsot' the lamp, or one such electrodemay be used in conjunction with a carbon electrode.

The prop0r any of the of the electrode thus formed tit) g l i In theaccompanying drawings I have in section an shown in elevation and part1e m the maninafter made to be limited to' the particular compositionsand the methods of producing electrodes set forth, more than is madenecessary 10 the state of the art.

. What I c aim as new and desire to secure by Letters Patent of theUnited States, is:

the spirit of my 1n- Witnesses:

composite arc-light electrode contaming carbid of boron.

2. A composite arc-light electrode containing apreponderating amount ofcarbid of boron.

3'. A composite arc-light electrode. composed of carbon, carbidofftitanium and carbid of boron.

4. A composite arc-light electrode containing carbon and-carbid. ofboron.

5. A composite arc-light electrode con taining carbid. of titaniunrandcarbid .of

boron.

In witness whereof, I have hereunto set my hand this 25th day of April,1905 JOHANNES HARDER BENJAMIN B. HULL, HELEH ORFORD.

